This invention relates to rockingly movable chairs particularly adapted for use in office work.
Conventional chairs used in office work comprise a seat horizontally mounted on a leg portion and a tiltable back which is normally biassed to a generally vertical position by a spring. The user of the chair can temporarily change his attitude by leaning on the back to relieve his fatigue. However, it has been difficult to maintain such attitude without forcibly leaning on the back. Further, the angle between the upper half and the lower half of the body of the user will change in changing the tilting angle of the back, which is not necessarily suitable for relieving his fatigue even though the back of the chair is locked at a desired tilting angle. It is preferable to maintain the angle between the upper and lower halves of the body at a predetermined range for minimizing fatigue and maximizing the efficiency of office work. Further, it has sometimes been required to maintain the angle between the upper and lower halves of the body at a predetermined range with the tilting angle of the seat or the back of the chair with respect to the horizontal surface being adjustable in some types of the work.
Further, it is publicly known that the fatigue can quickly be relieved by rockingly moving the chair back and forth.
Conventional chairs used in office work cannot satisfy the requirements aforementioned.